The market for how-to material has changed dramatically in recent years with the advent of the internet. For a start, how-to writing has always meant writing what you know about, but now your internet research means that you can widen your knowledge of any one subject to the point that you can simply write about about what interests you.
So, with a little homework, you could access enough information to write a how-to book about doggy health care. It doesn’t matter if you have accessed your information from dozens of online and other sources (and Suzanne Ruthven is good at sources) it is the bringing of it all together in a single source that can make a how-to book. Remember (as she advises) that if you can shape 45,000 words into ten chapters, each with ten sub-heads, you have the makings of a how-to book.
But whatever your subject you can bring your information together and shape it for print and internet markets the Suzanne Ruthven way.